Shield tunneling machine under-pressure bin opening and tool changing method

The invention discloses an under-pressure bin opening and tool changing method for a shield tunneling machine, and relates to the technical field of tunnel shield construction. The under-pressure bin opening and tool changing method for the shield tunneling machine comprises the steps that a mud film is manufactured and conveyed to the excavation end of a cutter head of the shield tunneling machine so as to support a soil body of a tunnel face, and then wall protection auxiliary construction is conducted; muck in a soil bin of the shield tunneling machine and muck on the side, close to the tunnel face, of a cutterhead are discharged, and air pressure supplementation is conducted in the soil bin; an automatic pressure maintaining system is started, and a pressure maintaining test is conducted in the soil bin; required articles and materials are transported to a material bin of the shield tunneling machine; gas safety detection is carried out in the human cabin; entering the main cabin, and pressurizing the mai